The edges of the Keeler gap

Mimas' shadow glides across Saturn

Cryovolcanoes on Enceladus

Titan's south polar vortex

NASA's Cassini spacecraft peers over the shoulder and through the rings of the second-largest planet in our solar system, Saturn. In the distance, Venus appears as a small, white dot.

The Cassini-Huygens mission -- which has been on location in the Saturnian system since 2004 -- is a cooperative project of NASA, the European Space Agency, and the Italian Space Agency. It is charged with 27 diverse science investigations.

The Saturnian system is large. The main ring system would barely fit in the space between Earth and the Moon. There are 31 moons -- 13 of which were discovered after Cassini launched. There's a lot for Cassini to see, including a variety of chemical, geologic, and atmospheric processes like suspected water ice, cryovolcanoes, and atmospheres rich in organic material.

In many ways, with its diversity and scale, Saturn could be considered the equivalent of a miniature solar system, scientists say.

Directly above the white streak of Saturn's G ring in the upper right portion of the image, Venus appears at dawn. In the lower part of the image is Saturn's E ring, colored blue due to the light scattered by dust in the ring.

Venus — along with Mercury, Earth, and Mars — is one of the rockier planets in the solar system. Though Venus has an atmosphere of carbon dioxide that reaches nearly 900 degrees Fahrenheit and a surface pressure 100 times that of Earth's, it is considered a twin to our planet because of its similar size, mass, rocky composition, and orbit.

The gravity from a small moonlet (nicknamed "Bleriot" by imaging scientists) scatters particles in Saturn's A ring and creates a propeller-like effect. This image was captured by the Cassini spacecraft on Nov. 11.

Near the lower right of Saturn's F ring, we see two "fans" of material radiating out of the core of the ring. Imperfections can be seen along the core. Dark "channels" cut into the main strand also can be seen in places. The channels are the result of a recent interaction with the shepherd moon Prometheus, which cannot be seen in this image.

Scientists believe that many of the F ring's diverse features are the result of interactions between ring material and either the shepherd moons or clumps of material within the ring.

The ring-region Saturnian moons Prometheus and Pan are both caught "herding" their respective rings in this image. Through the gravitational disturbances of nearby ring particles, one moon maintains a gap in the outer A ring and the other helps keep a ring narrowly confined.

Prometheus -- 53 miles across -- together with Pandora (which is not seen in this image) maintain the narrow F ring seen at the bottom left in this image. Pan -- 17 miles across -- holds open the Encke gap in which it finds itself embedded in the center. The bright dot near the inner edge of the Encke gap is a background star.

Saturn's small moon Daphnis' gravitational pull is responsible for disruptions in the rings that are causing these waves on the edges of the Keeler gap. The thin, dark band in the left half of this image was taken in visible light with the Cassini spacecraft's narrow-angle camera on Aug. 14. Waves like these allow scientists to locate small moons in gaps and measure their masses.

Saturn's moon Janus is barely visible in this image as a faint dot appearing above Saturn's north pole. Meanwhile, Mimas' shadow glides across Saturn. It can be seen in the southern hemisphere of Saturn, south of the rings' shadow.

Cryovolcanoes can be seen shooting large jets of ice particles into space on the south pole of Saturn's moon Enceladus. The shadow of the moon is slowly creeping up the jets, making the portions closest to the surface difficult to observe by the Cassini spacecraft.

The Cassini spacecraft spies Titan's south polar vortex from below the moon in this image taken with the Cassini spacecraft's narrow-angle camera on Sept. 13. To capture this image, a spectral filter was used. It is sensitive to wavelengths of near-infrared light centered at 889 nanometers. Imaging scientists are monitoring the vortex to study its seasonal development.